LTV =(old revenue – old costs)+ cashflow lag estimator * (current plan revenue to date – current plan costs to date)+ cashflow lag estimator * (future accrued revenue – potential remaining minutes cost * estimated utilization)
由于用户已经使用了一个月，因此我们本次套餐的确认收入（current plan revenue to date)为1000/12=83美元，然后提供这些课时的总体成本(current plan costs to date)为70美元。而未来可确认收入1,000-83=917美元。假设如果用户100%使用完对应套餐剩余课时的成本为900美元（这个数据因为套餐对应课时数不同而会有所差异），而套餐的预期使用率为80%。假设预期的套餐使用率基于历史上中国所有购买该套餐用户的平均使用率作为参考指标。
Stay at home as much as possible, and have few physical contacts with other people. This person may be your neighbor, your friends, or even your loved ones, but for each additional contact, the number of potential contacts will be increased by multiple times.
Please wear a mask whenever you need to leave your home. N95 masks provide the best protection, but if you can’t get them now, any ordinary mask or even any items that would help cover the mouth and nose can effectively reduce the infection rate. The major difference of each mask or other protection method is the infection rate that can be reduced.
If you live in an apartment, you need to wear a mask even when you go to the laundry room or use the elevator. If you have ever smelled smoke or food in the empty elevator, that is the aerosol that floats in the air which is different from droplets. So even if there is no one inside the elevator or on the corridor, there is still aerosol left in the air by the infected person. If the aerosol reaches a certain density, it will start to spread the virus. Besides, most corridors or elevators are not well ventilated, so there is a certain danger.
When wearing a mask, make sure that your breath is filtered through the mask. When you speak, the mask may move around. Please adjust it in time and make sure that your nose is not exposed.
Whenever you are outside, please do not touch your face or nose. Viruses on the mucous membrane will cause infection. If you have the habit of rubbing your eyes and touching your face, please wear gloves. Gloves can effectively remind you that it is not the best time to touch your face.
If you have to go to a crowded place with lots of people, please consider wearing goggles. If someone around you does not wear a mask, the droplets sprayed when they are talking will get into your eyes, which is also dangerous. Usually you do n’t need to buy special medical goggles, any goggles including swimming goggles, ski goggles, daily glasses or sunglasses can block splashing droplets. We don’t need medical goggles, as there will be less chance of being exposed to high density virus infection through the eye.
Reducing the use of delivery services, because the virus can survive on the surface of the object. It could survive up to a couple hours depending on the material. If you use delivery services, please make sure to spray them with alcohol or other disinfectants before taking them into the room and taking off the masks.
Please do not use alcohol spray to clean your masks, or any other “special” methods. A lot of experiments show that microwaves, ovens, and alcohol will cause damage to the protective layer of the mask, which is the core for protection. It’s important to save masks now, so please place the masks on the balcony or other ventilated place, dry it for one day, then you can wear it again. The N95 masks will last longer than other ordinary masks. If you feel your N95 mask blocks your breath, then maybe it’s time to replace it with a new N95 mask.
Some N95 masks have a breathing valve, which is a one way valve. If you have any suspicious symptoms, please avoid using a mask with a breathing valve, as your breath will go directly into the air without any filtering, which may be dangerous to your loved one or friends around you.
Wear the face mask all the time when you are outside and do not take it off, even inside your car. If you have your own parking garage, you can put your mask on after arriving at your destination and take it off when you are back home. If you park at a public garage, you need to put it on before you leave your house and take it off when you are at home.
Please wash your hands before taking off the mask, goggles and gloves, and do not touch the contaminated surface. To be more careful, you can wash your hands, every time you take off one item.
Please change the clothes and shoes when you are back home, and clean them, or place them in a ventilated place.
Do not directly touch any button or handles in public areas. If you have to, please wash your hands as soon as possible. It’s better to use a key, your elbow, or carry a pen to press the button.
If you have ever been to a high-risk area such as a hospital, don’t forget to clean your hair when you are back home.
Do not spray a wide range of disinfectants especially alcohol at home. It’s unnecessary, and would be dangerous.
If you are unable to purchase alcohol, please see if you can buy high alcohol liqueur (over 65%) like GRAFSKAYA VODKA.
Please try to avoid using the public restroom.
If there is any infection case nearby, in your community or building. Please follow the rules as below:
Self-quarantine for 14 days is a relatively safe period. In China, you will be required to quarantine at home or at a quarantine site for 14 days. During these 14 days, try not to have any physical contact with anyone.
Check your temperature regularly to see whether you have a fever, or have trouble breathing. If you have trouble breathing, you should call your doctor and go to ER immediately.
If you live in an apartment, immediately contact the leasing office and request disinfection for the public area.
If you live in an apartment, you need to pay special attention to the potential virus spread by sewers, which happened in SARS in Hong Kong(2003), and COVID-19 in South Korea and Mainland China (2020). If there are any infrequently used pools and drains in your home, please pour 1-2 liters of water regularly 2-3 times per week. The bent pipe structure of the sewer will pass through the accumulated water and block the air in the sewer from entering the house, but if it is not used for a long time, the water accumulated in the elbow will be evaporated and dry up, and lose its blocking effect.
When flushing the toilet, please close the toilet cover and flush. If there are disinfected effervescent tablets, you can put 2 tablets and wait for a while before flushing.
If you need to use the public laundry room, please wipe the buttons and other areas that you may touch, and then add disinfectant when washing clothes.
COVID-19 is highly transmissible, and there are many infection cases of short-period contact or even without direct contact in China. However, COVID-19 is also absolutely preventable and controllable. There are almost 40,000 medical workers from all around China to support Hubei Province, and over 30,000 to support Wuhan. As far as I know, none or few of those medical workers were infected as they have enough protection and are well-prepared when they went to Hubei Province.